GDM

Question 1

what are the risk factors for GDM?

Answer 1

1. BMI > 30
2. Previous macrosomic baby weighing ≥4.5kg
3. Previous GDM
4. 1˚ relatives with DM
5. Family origin with a high prevalence of DM (South Asian, black Caribbean, Middle Eastern)

Question 2

how do you screen for GDM?

Answer 2

1. Women with previous GDM:
   
   • OGTT after booking and at 24-28 weeks if 1st test normal
   • alternative: early self-monitoring of blood glucose
2. Women with any risk factors:
   
   • OGTT at 24-28 weeks

Question 3

what are the diagnostic thresholds for GDM?

Answer 3

1. FBG ≥ 5.6 mmol/l
2. 2-hour glucose ≥ 7.8 mmol/l

Question 4

how do you manage GDM?

Answer 4

1. newly diagnosed women: see in a joint diabetes and antenatal clinic within a week
2. teach self-monitoring of blood glucose
3. advice about diet (eat foods with a low glycaemic index) and exercise
4. if FBG <7mmol/l, a trial of diet and exercise should be offered
   
   • if glucose targets not met within 1-2 weeks, start metformin
   • if still not met, add insulin
   • ***GDM treated with SHORT-ACTING insulin
5. if FBG ≥7 mmol/l, start insulin
6. if plasma glucose levels 6-6.9 mmol/l + evidence of complications e.g. macrosomia/hydramnios => offer insulin
7. if cannot tolerate metformin/decline insulin rx => glibenclamide

Question 5

how do you manage pre-existing diabetes?

Answer 5

1. wt loss for women with BMI >27
2. stop oral hypoglycamic agents apart from metformin and commence insulin
3. folic acid 5mg/day from pre-conception to 12 wks gestation
4. detailed anomaly scan at 20 wks including four-chamber view of the heart and outflow tracts
5. tight glycaemic control reduces complication rates
6. treat retinopathy as can worsen during pregnancy